On Helpful Games, there are three types of membership: teacher, parent and student.
When you create your account as a teacher or parent, you select whether the account should be of type teacher or parent. This choice only affects the number of students you can create and the number of groups you may be responsible for:
Teacher account
With a teacher account, you may create 20 groups with 50 students in each group. This means that you can associate up to 1000 students to your account.
Parental account
With a parent account, you may manage 2 groups of 5 students in each group.
Student account
Student accounts can only be created by a teacher account or parent account when logged in.